Research on capacity

• Capacity

  The capacity of STM was established by Jacob 1887 who used a digit span test where the researchers reads out 4 digits and the participants recall it out loud in the correct order if this is recalled correctly the researcher adds on more numbers until the participants can’t recall the order correctly this indicates a person’s digit span He found that the mean span of digits across all participants were 9.3 items and 7.3 for letters
• The study is very old one and Early research in psychology Often lacked adequate control. For example some participants Digit spans might have been Underestimated because they Were distracted (confounding Variable).
• Miller research on capacity argued that things come in 7s and concluded that the capacity of STM is 7 items, plus or minus 2 To increase this capacity he said people chunk this information chunking is grouping sets of digits or letters into units or chunks.
• One limitation of Miller Research is that he may have Overestimated STM capacity, Nelson Cowan (2001)Reviewed other research and Concluded that capacity of STM is only about 4 plus of Minus 1 chunks. Therefore Miller estimate of 5 chunks Was more suitable.
• Capacity - ltm

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